Routing issue between LAN, OPT1 and Remote Subnet.

  • Sorry, I click a wrong button to create a poll, and can not find a way to delete it ;D

    Recently we employ a SIP trunk (4 channels) to our IP-PBX, and plan to use pfSense (v.1.23) to replace a old NetScreen 5GT(v.5). The network structure as below:

    ITSP provides a dedicate link and router for the SIP trunks. Unfortunately, the IP-PBX only has a LAN port. If the PBX directly connects to the SIP router, it works fine, but we lose all the IP phones. So, I have to setup a static route between the two subnets.

    The SIP trunks requires the PBX endpoint has the assigned IP which I assigned to OPT1. And use as the gateway to reach SIP server on ITSP site.

    I create a very lose firewall rule and allow the traffic from OPT1 interface to anywhere. A static route is created on LAN interface, to subnet should use gateway The SIP router and the OPT1 is linkup by a UTP.

    The problem is from pfSense LAN interface can not ping, not even But from OPT1 can reach From LAN just can only ping OPT1 I check the Route Table, it seems all right.

    Can any experts give me any idea about that. Thank you in advance.

    ![firewall rule.png](/public/imported_attachments/1/firewall rule.png)
    ![firewall rule.png_thumb](/public/imported_attachments/1/firewall rule.png_thumb)
    ![Static Route.png](/public/imported_attachments/1/Static Route.png)
    ![Static Route.png_thumb](/public/imported_attachments/1/Static Route.png_thumb)
    ![route staus.png](/public/imported_attachments/1/route staus.png)
    ![route staus.png_thumb](/public/imported_attachments/1/route staus.png_thumb)

  • Hi, I had some progress recently. Let me re-dram a simplify network diagram.

    ADSL Modem
    –--------------------------      -------------------------                ------------
    | WAN   OPT(|----| LAN1:|                |    ITSP     |          
    |                                   |     |SIP Router               |                |SIP Server|  
    |       pfSense                |      |                     LAN2:|------------||
    |                                   |      ------------------------                 ------------

    Lan (

    |      PBX         |

    I finally realized I should setup a Dual WAN configuration on my pfSense firewall. Because I can not touch the SIP router provided by ITSP, I can not setup a static route and tell the SIP router our LAN is on the other side. So, with a simple static route on pfSense won’t tell the packet come back to my LAN.

    I setup a gateway address ( under OPT1 interface. OPT1 just acts as another WAN port. After that, I can ping the SIP server at

    But the SIP call can not be established. According the other tutorial, I enable AON, I create NAT for LAN segment for both WAN port and OPT1 port, and make the static port for SIP 5060. For inbound NAT, I setup a rule for SIP UDP 5060, pointing to PBX at

    I have the incoming call working perfectly, but the outgoing calls still have problem. Because the SIP server will only accepts SIP Invite from authorize IP10.12.51.3. I use Wireshark to capture the packet, in the message header, the SIP Invite IP actually from the PBX IP rather than It seems a NAT problem, hopefully experts can give me some hints.

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